Technical Field
The present disclosure relates to an annular optical spacer and an imaging lens module. More particularly, the present disclosure relates to an annular optical spacer and an imaging lens module which is applicable to portable electronic devices.
Description of Related Art
Due to the popularity of personal electronic products and mobile communication products having camera functionalities, such as smart phones and tablet personal computers, the demand for compact imaging lens modules has been increasing, and the requirements for high resolution and image quality of present compact imaging lens modules increase significantly.
An optical spacer is generally used to provide an optical space between any two lens elements in an imaging lens module. A surface property of the optical spacer relates to an effect of suppressing unexpected lights. Accordingly, an image quality of the imaging lens module is influenced by the surface property of the optical spacer.
A conventional optical spacer is typically manufactured by an injection molding method. The optical spacer has a smooth and bright surface, which is featured with high reflectivity. As a result, the conventional optical spacer cannot suppress unexpected lights.
Another conventional optical spacer is provided for suppressing unexpected lights. The conventional optical spacer is atomized with a surface treatment, so that a reflectivity thereof is reduced. However, the effect of suppressing unexpected lights is still limited. Therefore, the conventional optical spacer cannot satisfy the requirements of high-end optical systems with camera functionalities.
Given the above, how to improve the surface property of the optical spacer for enhancing the image quality of compact imaging lens modules has become one of the important subjects.